Machine-switching telephone-exchange system.



I. N. REYNOLDS.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. I8. I9I5.

Patented Aug. 28, 191?.

3 SHEETS-SHEET I.

//7 I//V/OK' /0///7 Mewkawy Reyna/d5.

J. N. REYNOLDS.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 18 1915.

Patented Aug. 28, 1917.

3 SHEETSSHEET 2.

J. N. REYNOLDS.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED NOV. 18 l9l5.

Patented Au 28, 191.7.

a SHEETSSE4EET a.

' UNITED STATES PATENT OFFICE.

JOHN NEWBERRY REYNOLDS, OF GREENWICH, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

MACHINE-SWITCHING TELEPHONE-EXCHANGE SYSTEM.

Application filed November 18, 1915.

To all whom it may concern:

Be it known that I, J OIIN NEWBERRY REYN- OLDS, a citizen of the United States, residing at Greenwich, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Machine-Switching Telephone-Exchange Systems, of which the following is a full, clear. concise, and exact description.

This invention relates to telephone exchange systems employing machine switching.

In such systems it is the common practice to set up a connection over a chain of automa tic switches including what are known as trunk-lnlnting switches. These trunk-hunting switches are given a preliminary move-- ment in one direction in operative relation to the desired group of trunks, whereupon a locally controlled trunk-hunting action takes place to pick out the first idle trunk in the group. As is usually the case, if some of the trunks are busy, the selector brushes must travel over such busy trunks before finding an idle one. During this interval the next series of impulses may come in from the sender. This results in a false connection.

It is the object of this invention to avoid the necessity of a trunk-hunting action between the sets of impulses transmitted by the sender, thus avoiding the objection referred to, and decreasing the time necessary to set up a connection.

In accordance with this invention, a selector either individual to a calling line or associated therewith by suitable means upon the initiation of a call, is adapted to select, under the control of a sender, a line terminating in a magnet on a switch. This switch may be of substantially the same character as the switch described in applicants Patent No. 1,131,734, issued March 16, 1915. Each line-.represented in the row of contacts of the selector leads to a different trunk-selecting switch, lines from corresponding contacts of difierent selectors terminating in the same switch. Each such incoming line is represented on said switch by a shaft which controls multiple contacts of said line projecting at intervals from such shaft. Each trunk is represented on said switch by a shaft which controls multiple contacts of such trunk, one of these contacts Specification of Letters Patent.

Patented All". 28, 1917.

Serial No. 62,186.

lying adjacent to a multiple contact of each of the incoming lines. ()ne of the trunk shafts is displaced normally to maintain the contacts it controls in such a position that when a selector is set upon any incoming line and the magnet wherein such line terminates is energized, the shaft controlled by said magnet is actuated to cause a multiple contact of such line to engage the corresponding multiple contact of the trunk previously positioned, the other multiple contacts controlled by such incoming line shaft passing by the contacts controlled by the other trunk shafts,since such contacts are not displaced from their normal positions. Another idle trunk shaft is then immediately actuated by suitable mechanism to set its multiple contacts in operative relation to the multiple contacts controlled by the remaining incoming line shafts. The trunk lines terminating in this switch lead to selector switches of a certain group, and the initially operated selector, in selecting the desired incoming line, virtually selects the trunking-switch at which the desired group of trunks terminates. This trunking-switch will then connect the incoming line and an idle trunk of the desired group.

It will thus be apparent that no matter how many of the trunks terminating in such switch are in use, an idle trunk is associated almost instantaneously with any incoming line terminating in such switch when a call comes in over such line.

By virtue of this arrangement, the time interval between the arrival of the call on a line and the association of a trunk therewith is so small as to be practically negligible. The possibility therefore of the sender impressing the following series of impulses on a line before the selector in which such trunk terminates has become associated with such line is reduced to a minimum, and the time necessary to establish a connection substantially decreased.

Referring to the drawings, Figures 1 and 2, taken together, represent diagrammatically a telephone exchange circuit embodying this invention. Fig. 3 is an enlarged perspective View, with parts broken away,-

of the switch S, shown diagrammatically in Fig. 1, which is adapted to preselect an idle out-going trunk.

Referring to Fig. 3 of the drawings 1, 2,

3 and 4 represent frame members which are rigidly secured together, the opposite members being substantially parallel. Pivotally mounted between the members 1 and? is a plurality of line bars or shafts 5. Each of these bars is provided at one end with a right-angular extension 6 through which projects a pivot pin 7. The other end also has a right-angular extension 8 from which projects a pivot pin 9 received by an aperture in the frame member 3. Secured to the bars 5, but insulated therefrom and from each other, are three conducting strips 10, 11 and 12 provided with the integral multiply connected contact springs 13, 14 and 15 respectively. Each line bar would carry as many of these sets of contacts as there are trunk bars in the structure.

Pivotally mounted between the frame members 2 and 4 is a plurality of trunk bars or shafts 16, one being provided for each trunk or connecting circuit. These bars are pivotally mounted by means of the aperture in the right-angular extensions 17 and 18 at each end thereof receiving the pins 19 and 20 respectively. Secured to the bars 16, but insulated therefrom and from each other, are three conducting strips 21, 22 and 23. These strips are provided with a plurality of sets of integral spring contacts 24, 25 and 26 respectively, one set being provided for each line bar at the switch. These sets of springs project from the bars of the sets at their adjacent points or, in other words, at their points of intersection. Projecting from the extension 17 of each trunk bar is a catch lever 27 normally retained in retracted position by a spring 28. Pivotally secured to the bar 4 is a plurality of catch members 29, one for each trunk bar, adapted when the trunk bar is rotated in clockwise direction to engage and hold the catch member 27. Springs 30 are provided for holding the catch members in their operative position. Secured to the catch member 29 are armatures 31 of the trip magnets 32 respectively.

Rotatably mounted parallel to the bar 4 and adjacent to the levers 27 is a set rod 33. This rod is provided with a plurality of spirally arrangedpins 34, one for each lever 27 These pins are so arranged that one at a time, and only one, may be placed opposite to its respective lever 27, whereby upon longitudinal movement of the set rod 33 to the left, as viewed in the drawings, the trunk bar having the particular lever 27 engaged, will be rotated into set or selected position. This longitudinal movement of the rod 33 is caused by the armature 35 of the electromagnet 36 engaging the end of set rod 33, as clearly shown in the drawings.

Rotative with but slidably mounted on the rod 33 is a ratchet wheel 37, and operatively related thereto is a pawl 38 carried by the armature 39 of the electromagnet 40, by means of which the set rod may be rotated. Slidably but non-rotatably mounted on the bar 33, near the left end thereof, is a collar 41. Secured to this collar is a wiper 42 adapted upon rotation of the set rod 33 to traverse the test contacts 43. The wiper 42 is of sufficient size to bridge the distance between two adjacent test contacts 43. Mounted for wiping engagement with the collar 41 is a brush 44. A leaf spring 45, against which the end of the rod 33 bears, is provided for returning the set rod to its normal position. This spring is provided with a contact operating member 46 having projecting lugs 47 and 48. Cotiperating with the lug 47 is a pair of springs 49 and 50, contact between which is interrupted only at the moment the rod 33 reaches the end of its travel. Arranged for coiiperation with the lug 48 is a pair of contact springs 51 and 52. The spring 51 is provided with a cam projection 53. Upon the movement of the rod 33 to the left the lug engages the upper side of the cam projection 53. Upon the return movement, however, the lug 48 passes under the cam projection 53, causing a momentary engagement of contacts 51 and 52.

Mounted on the frame member 3, one for each line bar 5, is a plurality of electromagnets 55. Each magnet 55 is provided with a pivoted armature 56 having a right-angular projection 57 ending in a cam member 58. Projecting upwardly from each line bar 5 and in a position for engagement by its respective cam member 58 is a pin 59 by means of which the line bar may be rotated upon attraction of the armature 56. Upon further attraction of the armature 56, the shoulder 60 on the member 57 is arranged to engage the pin 9 in such a manner as to force the line bar to the left, as viewed in the drawing. Springs 61 and 62 are provided for returning the line bar to its normal position.

Secured to each trunk bar is an insulating projection 67 which, upon clock-wise rotation of the bar to its set or selected position, is arranged to engage and close the normally open contacts 68.

It is believed that the circuit shown in Figs. 1 and 2 will now be readily understood. In following this description it should be remembered that in normal position some one of the trunk bars or shafts 16 is always maintained in a set preselected position, that is, the catch lever 27 thereof is held to the left by its catch 29, and also that one of the pins 34 on the rod 33 is' in operative position to the lever 27 of a bar 16 associated with an idle trunk.

Referring now to Fig. 1, the removal of the receiver by the calling party causes the line conductors 116, 117 to be associated by a line finder (the brushes and cotiperating terminals only whereof are shown, since such switches are well known in the art), with conductors 134, 135 terminating in the stepping relay 111 of a selector D, which is adapted to be set under control of sender -s upon any line 130, 131, 132, terminating in a line bar 5 adapted to be rocked by its magnet 55 to seize the trunk 138, 139, 102 preselected. The circuit of relay 111 is as follows: free pole of battery, right winding of relay 111, side-switch arm 112, conductor 135, brush 5', terminals 0, line conductor 116, through the telephone set at substation A, line conductor 117, terminal a, brush conductor 134, side-switch arm 118, left winding of relay 111, to ground. Relay 111, at its armature and front contact, closes a circuit to energize a slow relay 119, which by attracting its right armature grounds conductor 136, thus energizing relay 140. Relay 140 interposes a break in the circuit of the release magnet 141 of selector 1).

The calling party now operates his sender s, which, in restoring, interrupts the circuit of relay 111 in the well-known manner. Upon the first interruption of the circuit, the armature of relay 111, in closing its back contact, energizesa slow relay 124. This relay, by attracting its armature, energizes the escapement magnet 122, which is arranged to release the side switch upon its de'e'nergization in the well-known manner. Each time the armature of relay 111 is retracted, an impulse is transmitted to the stepping magnet 123, which steps the brushes 127, 128, 129 over the terminals 130, 131, 132. When the sender returns to its normal position, the line circuit is again permanently closed, and the maintained energization of relay 111 causes the slow relay 124 to become deenergized. This relay, in releasing its armature, causes the deenergization of the escapement magnet 122, which releases the side switch into position 2. In position 2, side-switch arms 118, 112, 133 extend the circuit of conductors 134, 135, 136 into engagement with brushes 127, 128, 129. When the arm 133 moves into position 2, magnet 55 is energized in a circuit including conductor 99 and the armature and front contact of relay 119. .Armature 56 (Fig. 3) of said magnet is thereupon attracted, and through engagement of the cam 58 with the pin 59 on the line bar 5 causes said line bar to rotate. The rotation of the line bar 5 causes the contact terminals 13, 14 and 15 to move downwardly, thus positioning one set of terminals in operative relation to the contacts 24. 25 and 26 respectively of the set or preselected trunk 138, 139, 102. Upon the further attraction of the armature 56, the engagement of the shoulder 60 with pin 9 forces the bar 5 to the left, bringing the contacts of the line bar into firm engagement with the trunk terminals,

and also moving the unengaged terminals of the line bar to a position where they will not be engaged by the terminals on another trunk bar.

Upon engagement between contacts 15 and 26, a circuit is closed for electromagnet 32, which causes its armature to be attracted, carrying with it the catch member 29 (Fig. 3) and thus releasing the trunk bar 16, which is returned to its normal position by its spring 28. The terminals 24, 25, 26 of the set, which are in engagement with the terminals 13, 14, 15, however, remain in contact therewith due to the flexibility of said terminals. The other sets of terminals car- I ried by the trunk bar are rotated in an anticlockwise direction or to the right, as viewed in the drawings, to place them in a position where they will not be engaged by the terminals carried by the other bars 5. The engagement of contacts 13, 14, with 24, 25 respectively, closes the following circuit for the stepping relay 200 of the connector in which this trunk terminates: free pole of battery, upper winding of relay 200, middle armature of relay 201, conductor 202, conductor 138, contacts 24, 13, terminal 130, brush 127, arm 118, conductor 134, brush 7), terminal a, conductor 117, through the telephonic apparatus at substation A, conductor 116, terminals c,brush b, conductor 135, arm 112, brush 128, terminal 131, contacts 14, 25, conductor 139, conductor 203, inner armature and back contact of relay 201, lower winding of relay 200, to ground. Relay 200, in attracting its armature, energizes a slow relay 204, which, by attracting its armature, grounds conductor 205. This ground is placed upon conductor 205 before relay 119 (Fig. 1) denergizes, which occurs an interval after side switch arms 118, 112 move out of position 1 and remove stepping relay 111 from association with conductors 134, 135. The ground placed upon conductor 205 by relay 204 maintains magnet 55 and relay 140 energized.

The attraction of the armature 31 of magnet 32 (Fig. 3) closed its contact 84, thus completing a circuit for relay 85. Relay 85 is thereupon energized and attracts its armatures 89 and 90. The attraction of armature 90 completes a holding circuit for said relay through the winding 91, and contact springs 50 and 49. The attraction of the armature 89 completes a circuit from battery through set magnet 36. Magnet 36, by the attraction of its armature 35, causes the set rod 33 to move to the left, and by means of the finger 34, now in position to engage a lever 27 of the selected trunk causes the respective trunk bar to assume a set position ready for engagement by the terminals.

on the next bar 5 to be rocked.

As the engagement between contacts 49 and 50 is not broken until the set rod reaches approximately the end of its stroke, the complete travel of the rod is assured. When the rod reaches the end of its travel, the contacts 49 and 50' are separated, interrupting the holding circuit for the relay 85, causing its armatures to fall back, interrupting at armature 89 the circuit for the set magnet 36. The rod 33 thereupon returns to normal, closing momentarily in its passage the contacts 51 and 52, thus completing a circuit for the test relay 98 through said contacts. The relay is thereupon energized and attracts its armatures 100 and 101. The attraction of the armature 100 completes a holding circuit for the test relay, from battery, through its armature 100, brush 44, sleeve 41, brush 42, test contact 43, conductor 95, test conductor 102, right armature and front contact of relay 204, to ground. The attraction of the armature 101 completes a stepping circuit for the stepping magnet 40 from battery, winding of electromagnet 40 armature 101 and contact, through interrupter 105, to ground. The attraction of the armature-39 of electromagnet 40 causes through the pawl 38 the rotation of the set rod 33 to successively position the fingers 34 in operative relation to the levers 27 of the trunk bars. As long as the wiper 42 is in engagement with a test contact 43 of a grounded trunk line, the test relay will hold up and the stepping circuit will remain completed, the set rod being rotated by the successive energization and deenergization.

of the electromagnet 40 due to the breaking of its circuit by the interrupter 105. When, however, the wiper reaches a test contact 43 of an idle trunk, the test relay 98 will become deenergized. The retraction of the armature 101 will open the stepping circuit for the magnet 40, thus stopping the set rod 33 with one of the fingers 34 in operative relation to a lever 27.

The calling party now operates his sender in transmitting the tens digit of the called number. The sender in restoring, interrupts the circuit of relay 200 in the wellknown manner. Each time the armature of relay 200 closes its back contact, an impulse is sent to primary stepping magnet 206 of the connector. A slow relay 207 is included in this circuit, which relay, unlike the magnet 206, does not respond to the short interruptions of the circuit. Relay 207, in attracting its armature, closes a circuit to energize escapement magnet 208 of the side switch, which is arranged to release the side switch upon its dee'nergization in the well-known manner. When the sender restores and maintains the relay 200 energized, the slow relay 207 becomes deenerg1zed,-and in retracting its armature causes the deenergization of the escapement magnet 208. This magnet thereupon releases the side switch into position 2. In position 2, arm 209 of the side switch associates the secondary stepping magnet 210 with the back contact of the stepping relay 200. The sender is now operated to transmit the units digit of the wanted number. Each time the stepping relay 200' retracts its armature, an impulse is transmitted to the secondary stepping magnet 210 in a circuit including the slow relay 207. This relay, as before, by attracting its armature, energizes the escapement magnet 208. In the circuit of escapement magnet'208 is a relay 211, which, by attracting its armatures, opens the connec tion of conductors 212, 213 with connector brushes 214, 215 to prevent interference with existing calls. When the sender restores and maintains the line relay 200 energized, slow relay 207, after an interval, becomes denergized, causing the denergization of escapement magnet 208 and relay 211, assuming the line selected to be idle. Side switch arm 245 in moving into'engagement with its third contact, grounds multiples 219 to cause the selected line to test busy. Side switch arm 209, in movinginto position 3, prepares a circuit for a relay 220, which, when the constantly operating interrupter 221 reaches a metallic segment, becomes energized and connects the ringing generator 222 to the called line. The bell 234 of the called line is therefore intermittently rung to signal the wanted party. Upon the removal of the receiver by such party, while the interrupter 221 is upon an insulated segment, called supervisory relay 201 becomes energized over the following circuit: free pole of battery, right winding of relay 201, conductor 224, outer armature and back contact of relay 220, lower armature and back contact of relay 211, brush 215, contact 218, line conductor 225, through the telephonic apparatus at substation B, line conductor 226, contact 217, brush 214, upper armature and back contact of relay 211, conductor 212, inner armature and back contact of relay 220, conductor 227, conductor 228, left winding of relay 201, to ground. This relay, by attracting its outer armature, closes the following circuit to energize a relay 223: free pole of battery, arm 209, conductor 229, relay 223, conductor 230, outer armature and front contact of relay 201, conductors 231, 232, off-normal contact 233 of the connector, to ground. This relay, by attracting its left armature, locks itself over conductor 235 independently of the armature and contact of relay 201. Relay 223 maintains open the circuit of relay 220, thus permanently cutting off the ringing current.

Talking current is fed to the calling substation A over the windings of relay 200 and to substation B over the windings of relay 201 in the well-known manner. Relay 201, upon its energization when the called party responds, reverses the direction of the current flow in the calling line, which may operate a message register.

The release of the switches is controlled by the calling party, and occurs upon the replacement of his receiver, which in deenergizing relay 200 closes the following circuit for the release magnet 236 of the connector: free pole of battery, magnet 236, off-normal contact 237, armatures and back contacts of relays 204, 200 to ground. This circuit is opened when the connector reaches its normal position by the opening of offnormal contact 237. The release magnet in energizing restores the side switch in the well-known manner. Arm 209 of the side switch, in moving off its third contact,opens the locking circuit of relay 223. The connector apparatus is now entirely restored. Relay 204 in retracting its armature removes ground from conductor 205, which results in the deenergization of magnet 55 of switch S, and relay 140 of selector D. Magnet 55 in deenergizing, allows springs 61, 62 (Fig.3) to restore line shaft 5. Relay 140, in retracting its armature, closes the following circuit for release magnet 141 of selector D: free pole of battery, magnet 141, off-normal contact 142, armature and back contact of relay 140 to ground. hen selector D completely restores and opens its off-normal contact 142, release magnet 141 becomes deenergized.

Assume, however, that the selected line is busy when the connector brushes 214,215, 216 are set thereon. After the last interruption in the line circuit caused by the sender, the relay 207, after an interval, becomes denergized. A spring 239, controlled by the armature of this relay, is arranged to engage its contact 240 before said armature breaks contact with said spring. A busy line is one upon the test terminal 219 of which ground is present, as previously described. Consequently, when brush 216 engages such busy terminal, the following circuit is closed for theslde switch escapement magnet 208 to maintain the same energized and hold the side switch in position 2: free pole of battery, escapement magnet 208, relay 211, conductor 242, spring 239, contact 240, relay 241, spring 243 and its contact, conductor 244, side switch arm 245, conductor 216 to grounded termmal 219. The side switch magnet 208 and the relay 241 are thereby maintained energlzed. Relay 241 at its outer left armature opens the circuit of secondary stepping magnet 210 to prevent the calling party from further operating the connector. At its inner left armature said relay connects a busy back apparatus 245' to the calling line over the following circuit: busy back apparatus 245, conductor 246, said armature and its front contact, conductor 247 side switch arm 248 and its second contact to line conductor 203. The right armature, in engaging spring 243, closes a locking circuit for relay 241 independent of side switch arm 245 and grounded terminal 219. This circuit is as follows: free pole of battery, escapenient magnet 208, relay 211, conductor 242, spring 239, contact 240, relay 241, spring 243, right armature of said relay, conductors 248, 232, off-normal contact 233 of the connector to ground. \Vhen the calling party restores his receiver to its switchhook, the release of the switches is effected as previously described in connection with a successful call. When the connector restores, the opening of ofi'-normal contact 233 unlocks relay 241.

While only one selector D and trunking switch S are shown, in large exchanges a connection would lead over a number of such switches.

WVhat is claimed is:

1. In a telephone exchange system, the combination with incoming lines, trunk lines, a switch comprising multiple contacts for each incoming line and corresponding multiple contacts for each trunk line, and means for causing the multiple contacts of an idle trunk line and of all incoming lines to be placed in operative relation to each other, a selector associated with each of said incoming lines, a sender for transmitting impulses to a selector to select the particular incoming line associated therewith, and means arranged to cause engagement between a multiple contactof the selected incoming line and the corresponding contact of the idle trunk line when said selector is set on said incoming line.

2. In a telephone exchange system, the combination with incoming lines, trunk lines, a switch comprising multiple contacts for each incoming line, a shaft for each incoming line controlling its multiple contacts, multiple contacts for each trunk line, a shaft for each trunk line controlling its multiple contacts, said trunk line shafts and incoming line shafts intersecting each other, and

means associated with the trunk line shafts for maintaining an idle one thereof normally displaced, a sender, a selector controlled thereby for selecting one of said incoming lines, and an electromagnet for each incoming line shaft adapted upon the selection of said line by said selector to actuate its shaft to cause engagement between a multiple contact thereon and the corresponding trunk contact displaced by the shaft of the preselected trunk line.

3. In a telephone exchange system the combination with subscribers lines, senders thereat, incoming lines, trunk lines, a switch comprising multiple contacts for each incoming line, a shaft for each incoming line controlling its multiple contacts, multiple contacts for each trunk line, a shaft for each trunk linc controlling its multiple contacts, said incoming line shafts and said trunk shafts intersecting each other, and means associated with said trunkline shafts for maintaining an idle one thereof normally displaced, and an electromagnet for each incoming line shaft adapted upon the selection of said line to actuate its shaft to cause engagement between a multiple contact thereon and the corresponding displaced multiple trunk contact controlled by the shaft of the preselected trunk.

4. In a telephone exchange system, the combination with telephone lines, senders associated therewith, incoming lines, a selector adapted to be associated with a calling line and controlled by the sender thereof to select one of said incoming lines, trunk lines, a switch comprising multiple contacts for each incoming line, a shaft for each incoming line carrying its multiple contacts, multiple contacts for each trunk line, a shaft for each trunk line carrying its multiple contacts, said trunk line shafts and incoming line shafts intersecting each other, means associated with said trunk shafts for maintaining an idle one thereof normally displaced, and electromagnets for said incoming line shafts adapted upon the selection of an incoming line to rock the shaft thereof to cause engagement between a multiple contact thereon and the corresponding displaced trunk contact controlled by the shaft of the preselected trunk line.

In a telephone exchange system, a switch, an incoming line and outgoing lines terminating at said switch, a sender for transmitting impulses to said switch to connect said incoming line to a definite one of the outgoing lines, asecond switch at which the outgoing line terminates at the opposite end thereof, trunk lines terminating at said second switch, means at said second switch for preselecting an idle trunk line and means operated when said incoming line is connected to said outgoing line for causing 'said second switch to connect said outgoing line to an idle preselected trunk.

6. In a telephone exchange system, a switch, an incoming line and outgoing lines terminating at said switch, each of said outgoing lines corresponding to a different group of subscribers lines, a sender for transmitting impulses to said switch to connect said incoming line to a definite one of the outgoing lines, a second switch at which the outgoing line terminates at the opposite end thereof, trunk lines terminating at said second switch, means at said second switch for preselecting an idle trunk line and means operated when said incoming line is connected to said outgoing line for causing said second switch to connect said outgoing line to an idle preselected trunk.

In witness whereof, I hereunto subscribe my name this 16th day of November, A. D. 1915.

JOHN NEWBERRY REYNOLDS. 

